Immunological responses in Sjogren's syndrome and rheumatoid arthritis.

Cellular and humoral immune responses have been measured in patients with Sjøgren's syndrome with, and without, rheumatoid arthritis, patients with sero-positive and sero-negative rheumatoid arthritis, and a control group of patients. Several patients with sero-positive rheumatoid arthritis and patients with Sjøgren's syndrome complicated by rheumatoid arthritis failed to respond to 2–4 Dinitrochlorobenzene, and exhibited poor secondary responses to tetanus toxoid. Mantoux responses, however, were diminished only in patients with the sicca syndrome. Estimation of RNA/DNA ratios of peripheral blood lymphocytes showed increased ratios in those groups of patients responding poorly to DNCB and tetanus toxoid. As the lymphocyte RNA/DNA ratio is correlated to mean lymphocyte diameter, this means that patients with elevated ratios have an absolute, or relative, increase in the number of large lymphocytes circulating in the peripheral blood. It is suggested that failure to respond to DNCB may be due to a deficiency of uncommitted small lymphocytes.